The present invention relates to a method and apparatus for continuously conveying works by circulatingly moving a plurality of conveying carriages for supporting the works.
Various work conveying apparatuses have been proposed and in practical use. A typical work conveying apparatus has been arranged to dispose a conveying rail above a returning rail. A plurality of conveying carriages are circulated between the conveying rail and the returning rail through a pair of lifter mechanisms. More specifically, a conveying carriage conveyed on the conveying rail is transferred to the returning rail through a carriage receiving base, a carriage put-out mechanism, the lifter mechanism and a carriage put-in mechanism. Similarly, the conveying carriage conveyed on the returning rail is transferred to the conveying rail through a carriage receiving base, a carriage put-out mechanism, the lifter mechanism and a carriage put-in mechanism.
However, such a conventional work conveying apparatus is complicated in structure and operation, and therefore a cycle time of this apparatus is limited by these complicated structure and operation.
It is an object of the present invention to provide an improved work conveying apparatus and method which is simplified in structure and operation and improves its operation speed thereby to decrease a cycle time in operation.
An aspect of the present invention resides in a work conveying apparatus which comprises a conveying rail and a returning rail, a starting-stage selector rail, a terminating-stage selector rail, a plurality of conveying carriages and a carriage drive mechanism. The returning rail is disposed along the conveying rail. The starting-stage selector rail is parallel to the conveying rail and is swingable between a first position straightly extending from an end of the conveying rail and a second position straightly extending from an end of the returning rail. The terminating-stage selector rail is parallel to the conveying rail and is swingable between a third position straightly extending from the other end of the conveying rail and a fourth position straightly extending from the other end of the returning rail. A plurality of conveying carriages are conveyed on the conveying rail and the returning rail to convey works from the starting-stage selector rail through the conveying rail. A carriage drive mechanism moves the conveying carriages on the conveying rail, the return rail, the starting-stage selector rail and the terminating-stage selector rail. The carriage drive mechanism comprises a reciprocating member and a supporting member, the reciprocating member being disposed along the conveying rail and being reciprocatingly movable along the conveying rail, the supporting member is connected to the reciprocating member and being selectively connected to a portion of each of the conveying carriages.
Another aspect of the present invention resides in a work conveying apparatus comprising a conveying rail, a returning rail disposed along the conveying rail, and a starting-stage selector rail parallel to the conveying rail. The starting-stage selector rail is swingable between a first position straightly extending from an end of the conveying rail and a second position straightly extending from an end of the returning rail. A terminating-stage selector rail is parallel to the conveying rail, the terminating-stage selector rail being swingable between a third position straightly extending from the other end of the conveying rail and a fourth position straightly extending from the other end of the returning rail. The apparatus also includes a plurality of conveying carriages moved on the conveying rail and the returning rail, the conveying carriage conveying a work from the starting-stage selector rail to the terminating-stage selector rail through the conveying rail. The apparatus further includes a carriage drive mechanism moving the conveying carriages on the conveying rail, the return rail, the starting-stage selector rail and the terminating-stage selector rail, the carriage drive mechanism comprising a carriage conveying mechanism which moves the conveying carriages disposed on the conveying rail and the starting-stage selector rail set at the first position in a conveying direction, and a carriage returning mechanism which moves the conveying carriages disposed on the returning rail and the terminating-stage selector rail set at the fourth position in a returning direction. The carriage conveying mechanism comprises a conveying finger lever connected to the conveying carriage and a carriage transfer mechanism which is disposed under the conveying rail, the carriage transfer mechanism reciprocatingly moving the conveying finger lever along the conveying direction.
Yet another aspect the present invention resides in a work conveying apparatus which comprises a conveying rail, a returning rail disposed along the conveying rail, and a starting-stage selector rail parallel to the conveying rail. The starting-stage selector rail is swingable between a first position straightly extending from an end of the conveying rail and a second position straightly extending from an end of the returning rail. A terminating-stage selector rail is parallel to the conveying rail, the terminating-stage selector rail being swingable between a third position straightly extending from the other end of the conveying rail and a fourth position straightly extending from the other end of the returning rail. The apparatus also includes a plurality of conveying carriages moved on the conveying rail and the returning rail, the conveying carriage conveying a work from the starting-stage selector rail to the terminating-stage selector rail through the conveying rail. The apparatus further includes a carriage drive mechanism moving the conveying carriages on the conveying rail, the return rail, the starting-stage selector rail and the terminating-stage selector rail. The carriage drive mechanism comprises a carriage conveying mechanism which moves the conveying carriages disposed on the conveying rail and the starting-stage selector rail set at the first position in a conveying direction, and a carriage returning mechanism which moves the conveying carriages disposed on the returning rail and the terminating-stage selector rail set at the fourth position in a returning direction. The carriage returning mechanism comprises a returning finger lever connected to the conveying carriage and a carriage transfer mechanism which is disposed under the conveying rail, the carriage transfer mechanism reciprocatingly moving the returning finger lever along the returning direction.
Still another aspect of present invention resides in a work conveying apparatus which comprises a conveying rail, a returning rail disposed along the conveying rail, and a starting-stage selector rail parallel to the conveying rail. The starting-stage selector rail is swingable between a first position straightly extending from an end of the conveying rail and a second position straightly extending from an end of the returning rail. A terminating-stage selector rail is parallel to the conveying rail, the terminating-stage selector rail being swingable between a third position straightly extending from the other end of the conveying rail and a fourth position straightly extending from the other end of the returning rail. The apparatus also includes a plurality of conveying carriages moved on the conveying rail and the returning rail, the conveying carriage conveying a work from the starting-stage selector rail to the terminating-stage selector rail through the conveying rail. The apparatus further includes a carriage drive mechanism moving the conveying carriages on the conveying rail, the return rail, the starting-stage selector rail and the terminating-stage selector rail. The carriage drive mechanism comprises a carriage conveying mechanism which moves the conveying carriages disposed on the conveying rail and the starting-stage selector rail set at the first position in a conveying direction, and a carriage returning mechanism which moves the conveying carriages disposed on the returning rail and the terminating-stage selector rail set at the fourth position in a returning direction. The carriage returning mechanism comprises a starting-stage sprocket disposed in the vicinity of said starting-stage selector rail, a terminating-stage sprocket in the vicinity of the terminating-stage selector rail, an endless chain wound around the starting-stage sprocket and the terminating-stage sprocket, a return projection which is projected from each of the conveying carriages, and a plurality of fixing projections installed to the endless chain at predetermined intervals, the fixing projections being in contact with the return projections, respectively, when the conveying carriages are returned from the terminating stage to the starting stage.
Another aspect of the present invention resides in a work conveying method which comprises a step for moving a plurality of conveying carriages continuously set on a conveying rail and a starting-stage selector rail by one pitch in a conveying direction; a step for detaching a work from the conveying carriage set on the terminating-stage selector rail; a step for displacing the starting-stage selector rail and a terminating-stage selector rail from first positions straightly extending from ends of the conveying rail to second positions straightly extending from ends of a returning rail; a step for moving the plurality of the conveying carriages continuously set on the returning rail and the terminating-stage selector rail by one pitch in a returning direction; a step displacing the starting-stage selector rail and the terminating-stage selector rail from the second positions to the first positions; and a step for attaching a work to the conveying carriage set on the starting-stage selector rail.